Various methods have been used to heat cooking chambers of ovens. One such method entails transferring heat generated by combustion of combustible fuels to the cooking chamber. The fuel is generally combusted in a combustion chamber that is located adjacent to the cooking chamber. In a common application, the combustion chamber will be located below the cooking chamber to take advantage of the thermal rise that accompanies the relatively low density hot gas produced during combustion. The hot gas may directly or indirectly heat the walls of the cooking chamber. For example, hot gas produced in the combustion chamber may directly heat a wall of the combustion chamber and thereafter escape the oven via a flue. The wall then radiates the heat to the adjacent cooking chamber, which is generally located along a common wall. Instead of directly exhausting the gas from the combustion chamber through the flue, some ovens route the hot gas through the cooking chamber prior to exhausting it through the flue.